2. Prime and Composite Numbers A prime number is a natural number greater than 1 whose only factors are 1 and itself. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29,... A composite number is a natural number greater than 1 that is not prime.

3. The natural number 1 is neither prime nor composite. Helpful Hint

4. Prime Factorization A prime factorization of a number expresses the number as a product of its factors and the factors must be prime numbers.

5. Remember a factor is any number that divides a number evenly (with a remainder of 0). Helpful Hints

6. Prime Factorization Every whole number greater than 1 has exactly one prime factorization. 12 = 2 2 3 2 and 3 are prime factors of 12 because they are prime numbers and they divide evenly into 12.

7. Examples 1Write each number as a product of primes. a)120 b)640 c)2520